I've been using the Raptor Guru (with the Competitor) for almost 2 years, and it works great. If your BS is protected from the sun generally you can maintain cabinet temperatures of +/-2°F. In mild wind conditions, such as winds up to about 15 mph, it has no problem maintaining your cabinet temperature. At one point I was thinking about purchasing the Procom 4, but couldn't justify it. Though if I had the money that is the way I would go. I don't have any knowledge of the Pit Minder. The set up I have works great. The only thing that bothered me for a short period of time was looking at a display that had LED lights that indicated a range of temperature.
If you already have the Competitor you only need to purchase the Raptor power unit. If you do decide to purchase the Raptor Guru, give some thought into ordering the 6' thermocouple instead of getting the standard 4' length (I believe if you send them an e-mail, or better yet call, they will switch the lengths and adjust the price accordingly. With the 6' cord you can set the Competitor on the generator; away for the smoke vent, and still have plenty of cord to run it through the vent. If you do a search on forum member SmokeHouseRob on the Guru, he used a magnet to attach the Competitor to the side of the BS, if you use his idea then the 4' cord will be long enough.
Good luck with your decision.